U.S. Pat. No. 3,516,460, Thrasher discloses a system for mounting circular saws on an arbor while allowing the saw to float axially on the arbor. The saw is guided between a pair of guides. The Thrasher saw has a scalloped opening that fits around an arbor having a large number of small rounded splines. The Thrasher system permits reasonably accurate thin cuts with the use of thin circular saws guided by saw guides. The use of guided saws which can "float" (i.e. which can move at least slightly longitudinally) on an arbor, while the arbor is turning, has become widely accepted in the saw milling industry.
Typical arbors for mounting and driving guided saws have 18 to 22 rounded splines and are 5 inches to 8 inches in diameter. There are standard sizes and configurations for such arbors. One problem that is now being experienced in the saw milling industry is that "standard" sized splined arbors from different manufacturers are often different sizes. This is partly due to the fact that conventional prior art arbors are very difficult to accurately machine with standard machining techniques. There are several manufacturers of saw arbors. To enable their blades to fit the arbors of all arbor manufacturers, saw blade manufacturers typically make the eyes in their circular saws oversized by as much as about 0.030 inches. The poor fit of a saw on an arbor can cause the saw to "pound" as the arbor turns. This happens despite the fact that most arbors used today have rounded splines, which, in theory, makes them self-centering to some degree. The pounding can spread the eye of the saw which makes the pounding even worse.
Another problem with prior art saws is that, unless the splines and saw are both perfectly machined, which is impossible, not all of the splines engage the eye of the saw when the saw is being driven.
Another problem experienced in saw mills is that the forces exerted on a saw by the lobes in a prior art arbor result in repeated shocks being delivered to the saw blade in a region concentrated around the eye of the saw. These problems are exacerbated because conventional arbors provide only a very small driving contact area between the arbor and a saw blade.
Some have attempted to reduce these problems by providing a more accurately machined saw and arbor which fit together to very close tolerances. This approach has not been entirely satisfactory because, with arbors of conventional design, close tolerances between saw and arbor tend to increase the likelihood that the saw will "bind" on the arbor and will not float freely along the arbor as is desired. Furthermore, it is not possible with common current techniques to cut the eye of a saw to an accuracy of better than about .+-.0.002 inches. Further, such arbors still provide only a very small contact area.